mus/ash: WmRootWindowController can be null in mus.

mus/ash: WmRootWindowController can be null in mus.

ash_sysui ideally wouldn't need to create the ShelfLayoutManager, but it's too
deeply ingrained to take out right now. When running in ash_sysui, the shelf
widget's 'root window' is not one of the root-windows ash::Shell instance knows
about, so it doesn't have a WmRootWindowController. So check for its existence
before adding an observer to it.

BUG=603369
R=sky@chromium.org

Committed: https://crrev.com/fa1ae588e0fcda6bda31557a32b4848d8018530a
Cr-Commit-Position: refs/heads/master@{#390541}

[sky, 2016-04-28 15:23:12]

https://codereview.chromium.org/1916913007/diff/1/ash/shelf/shelf_layout_mana...
File ash/shelf/shelf_layout_manager.cc (right):

https://codereview.chromium.org/1916913007/diff/1/ash/shelf/shelf_layout_mana...
ash/shelf/shelf_layout_manager.cc:242: DCHECK(Shell::GetInstance()->in_mus());
What about wrapping this whole thing in !Shell::GetInstance()->in_mus()?

[sadrul, 2016-04-28 15:28:51]

https://codereview.chromium.org/1916913007/diff/1/ash/shelf/shelf_layout_mana...
File ash/shelf/shelf_layout_manager.cc (right):

https://codereview.chromium.org/1916913007/diff/1/ash/shelf/shelf_layout_mana...
ash/shelf/shelf_layout_manager.cc:242: DCHECK(Shell::GetInstance()->in_mus());
On 2016/04/28 15:23:12, sky wrote:
> What about wrapping this whole thing in !Shell::GetInstance()->in_mus()?

Done.

[sky, 2016-04-28 23:53:35]

LGTM

[sky, 2016-04-28 23:53:44]

The CQ bit was checked by sky@chromium.org

[commit-bot: I haz the power, 2016-04-28 23:54:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1916913007/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1916913007/20001

[commit-bot: I haz the power, 2016-04-29 00:03:19]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-04-30 17:22:54]

Patchset 2 (id:??) landed as
https://crrev.com/fa1ae588e0fcda6bda31557a32b4848d8018530a
Cr-Commit-Position: refs/heads/master@{#390541}

[commit-bot: I haz the power, 2016-04-30 17:58:30]

Description was changed from

==========
mus/ash: WmRootWindowController can be null in mus.

ash_sysui ideally wouldn't need to create the ShelfLayoutManager, but it's too
deeply ingrained to take out right now. When running in ash_sysui, the shelf
widget's 'root window' is not one of the root-windows ash::Shell instance knows
about, so it doesn't have a WmRootWindowController. So check for its existence
before adding an observer to it.

BUG=603369
R=sky@chromium.org
==========

to

==========
mus/ash: WmRootWindowController can be null in mus.

ash_sysui ideally wouldn't need to create the ShelfLayoutManager, but it's too
deeply ingrained to take out right now. When running in ash_sysui, the shelf
widget's 'root window' is not one of the root-windows ash::Shell instance knows
about, so it doesn't have a WmRootWindowController. So check for its existence
before adding an observer to it.

BUG=603369
R=sky@chromium.org

Committed: https://crrev.com/fa1ae588e0fcda6bda31557a32b4848d8018530a
Cr-Commit-Position: refs/heads/master@{#390541}
==========